Die casting controlling mechanism



Nov.v5, 1957 B. F. HOLMES ETAL 2,811,758

DIE CASTING coNTRoLLING MECHANISM Filed Sept. 18,v 1956 10 Sheets-Sheet 1 ,4 from/5y Nov. 5, 1957 B. F. HOLMES ETAL 2,811,758

DIE CASTING CONTROLLING MECHANISM-- Filed Sept. 18, 1956 10 Sheets-Sheet 2 Nov. 5, 1957 iled SeptJ 18, 1956 HAE JOVVY B. F. HOLMES TAL 2,811,758

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B. F. HOLMES ET AL DIE CASTING CONTROLLING MECHANISM y Nov. 5, 1957 10 Sheets-Sheet 6 Filed Sept. 18, 1956 INVENTOR.s

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DIE CASTING CONTROLLING MECHANISM Filed Sept. 18, 1956 10 Sheets-Sheet '7 HvJ/m9 sunsssud N m W A TTOA/E Y Nov. 5, 1957 B. F. HoLMEs ET AL 2,311,753

DIE CASTING coNTRoLLxNG MECHANISM Filed Sept. 18, 1956 lJ70 ShGSS-Sheet 8 Compressed Anf' .Supp

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DIE CASTING coNTRoLLrNG -MECHANISM 1:0 Sheets-Sheet 10 Filed Sept. 18, 1956 W Wmv GNN.

United States Patent() DIE CASTING CONTROLLING MECHANISM Burton F. Holmes and Herbert H. Heindel, Toledo, l1io,

assignors to Schultz Die Casting Company, Toledo,

This invention relates to an automatic control mech'- anism for die casting machines, including an extremely accurate `controllable means in a die casting machine increasing the productivity thereof, and the eiciency and safety of the operations of die casting, this application being a continuation-in-part of vour prior application, Serial Number 196,914, tiled Novembel 21, 1950, now abandoned, which was a division-of our prior application, Serial No. 790,83 8, tiled December 10, 1947, for Method of Die Casting, now Patent No. 2,532,256, issued N vember 28, 1950.

yThis present invention relates tothe mechanism of such a machine and has for its object the provision of automatic means for accomplishing such results by controlling and operating the die casting machine including two uid motors interlocked in operation one for the die opening and closing means, and the other yfor the metal injection in two stages with a more accurate control r operation and timing of the actuating mechanisms; therefor. y

Further objects of the invention include the provision of such improved automatic die casting controlling and operating means in which in one embodiment thereof a pressure plunger is operated in two stages in which'an adjustable time controlling mechanism is employed for effecting operation of the plunger to partially iillpthe die during the rst of the two stages and adjustable time controlled means for moving saidl plunger atfa higher rate of speed during the second stage of the metal injection to thereby completely and properly llfthe molding cavity, with specific intercontrols between the specific two stage metal injection and the die closing and opening means for more perfect interaction and increased eiiiciency production. f

Thus, a further object of the present invention isv to provide in our improved cie casting machine' particularly eicient safety controlling mechanisms in' which a double control is incorporated to prevent injection of metalinto the die cavity in case the mold is not completely'closd, and further safety control mechanisms are interconnected throughout the system in which in the means employed herein, energy is stored in the operating controlling'mechanism with the use of restraining means to preventactuation thereof until the exact time controlled by the timing mechanism, said safety control being interconnected- 'with said restraining means. n

Further objects and advantagesare within the scope of this invention, such as relate tothe arrangement, operation and function of the related elements of the'stiucture, to various details of construction and to combinations of parts, elements per se, and to economies of 'manufacture and numerous other features, as will be apparent from a consideration of the specification and drawing 4iof a form of the invention, which may be preferred-in which:

Figure I is a diagrammatic View of `one type ofl die f 2,81 1,758 Patented Nov. 5, 1957 ICC casting machine to which our invention has been applied- Figure I representing the operation of the uid motor and mechanism for closing the dies;

Figure II is a diagrammatic view similar to Figure I, in

which a preliminary or delayed injection of the casting metal operation is taking place;

Figure III is a similar diagrammatic illustration of the machine during the main injection operation;

Figure IV is a cross sectional view of a detail of the metal injecting plunger and cylinder;

Figure V is a diagrammatic illustration similar to Fig. III showing the cooling time of the machine with the air control piston returning to normal position;

Figure VI is a diagrammatic illustration of a mechanism illustrating the opening of the dies;

Figure VII is an electrical diagram of a control embodying our invention as applied to the type of mechanism illustrated in Figures I through VI;

, y Figure VIII is a View similar to Figure VII of a modivication of the circuits and respective controls thereof;

Figure IX is an elevational View partly in section of a modied type of die casting mechanism using the present invention;

Figure X is a sectional elevation showing one embodiment of a valve controlling the motor for the die opening and closing mechanism, said valve being shown in position for opening the dies; g

Figure XIis a section through the valve of Figure X, showing the parts in position for closing the dies;

Figure XII is a sectional elevation of one embodiment ofa main and check valve mechanism, employed in operating the metal injecting iiuid motor, the parts being shown in position for slow injection; r

Figure XIII is asection through the check valve of Figure XII, the parts being in position for rapid injection;

t Figure XIV is a section on the line XIV-XIV'V of Figure XII; y

Figure XV is a section on the line XV-XV of Figure XII. Y Y y In certain embodiments of our invention, we have illustrated the same as incorporated with the type of die casting machine illustrated in the prior patents to Schultz et al. for Method for Casting Metals, Patent No. 2,108,080,'dated February 1938, and to Schultzvet al. ,for

Apparatus for Casting Metal, Patent No. 2,173,377,

`metal injection mechanism with a special construction and interconnected arrangement of such mechanisms, said control involving a series of means and controlsfwith manually adjustable means to time the operation of said pneumatic and fluid mechanisms. The operation of the machine involves the following main steps: l

(l) Machine closing-die closing, illustrated inpFigure I.

` (2) Casting metal injection started (sloW)-illustrated in Figure n. j

(3) Heavy shot oftcastingy metal (fast)-illustrated in Figure III. y

(4) Pressure held on the metal in closed dieA with the parts in the position as illustrated in Figure III. (f5) Returnof the vmetal injecting piston to normal position-illustrated in Figure V. l Y

(6) Machine opening-die opened, illustrated in FigureVI.v l i i The main control 'of the die casting operationis by one hydraulic mechanism (for die operation)V and its operating valve and two uid motors or mechanisms with c'z'ontrclledvalves for the second motor or the pneumatic mechanism, the valves for both motors operated through the network disclosed, so that the proper operations of these valves and thehydraulic airmechanisms. or motors control the machine operation step by step, as indicated.

As indicated above, the present case relates. toa division of our prior case relating to a method of die casting, whereas, the present case is concerned, with interconnected operating mechanisms and controls for an eicient and safety operation of a die casting machine. In the present case, the illustrated controls are by an electrical system, including the special mechanism for producing the die opening and closing and the two-stage metal' injection with adjustable meansV extending throughout the entire range of operationl of the machine; to a special' temporary locking device for preventingA improper operation o f the machine untily the completion of onel cycle thereof;J to a special safety arrangement of interconnected' mechanisms in which ay controlling partl has ar two-position location, one for effecting die closing, theothery f or effecting metal injection together withy controlling means, the operation of which depends upon the position. off said two-position controlling means; to a combination thereof,in,l which dual safety control mechanisms arel employed together with simultaneously operating pressure controllingmeans producing a triple safety c ontrol and, special interconnections with theY power supplying means.,

Referring in more detail to the particular type illusi and when it is closed, the 24-volt current isisupplied to i the main manual quick return control huttonon starting switchmarked 23 in Figure` VII, and 23,- in Figure VIII.

This main control button 23l is a momentarily operated t typewhich, whenpressed by the operator, suppliescurrent toI the relay 2,0, energizing the relay thereby.- closing points` 21 which are thereupon held closed continuing thereafter to maintain the machine in automatic control for one complete cycle all.aswill hereinafter be. mor`e fully described. The machine then automaticallwstops so that the operator may removethe; casting.. All parts of the machine are then in proper'positionfor,recycling theoperation andthe. operator may continueproducing castings at will. A

Theirst operation-closing. the dies (Figure-` I) isaetfected by tiring of the l thyratron` (orspace. diSchB-r?) tube 5. The tube 5 is, until firing, underfanormalrbias of 7.5 volts. Whenv the relay. 20 is energizedfdtfalso operates point 2.4. which short circuitstherbiascircuit to the grid of tubieS` through the condenser` 25.,andr.re. sistance 26. This action of removing thebias .frorntube 5 causes the `same to re (throughithe, timefdelayrmentioned), and Athis operates relay 10,. its corresponding com tacts andsupplies` 440 volts to the main oiLpilotjvalve solenoid for. closing the die .casting,machine.:, More specifically, the` oil motor shownhaving piston 60a.-for closing the dies (shown in Figs. I-VI)` operates'thenmech.- anism-illustrated -for movingthe` movable `liefB to, and away from the Xed die A. An oil pump and supply lines ,are also shown and arrangedfto.,movecpistom 60a of the oil fluid motor 60 in one directionor the,other dependent upon thek position ofthe valve 63a,-;=which in i turn is moved to the position of Fig. I by saidfenergization of solenoid 30 to start closing-the` diesvwhile piston 60a is moved inthe opposite direction tovopennthe. dies whenlvalye 63a is turned tothe other; position shown i in Fig. VI by spring X when said solenoidg-.iszldeenergized.

When machine closes, microswitch illustrated diagrammatically at 27 whichis normally open-, also closes,;there by applying 24 volts to` relay coilj33.; kela-yrhaa threerelay points normally closed which'apply ,biastoriubusfl 2 and` `3. When coil 33 `is energized;theseJ-threecpgini of relay 33 open, and the bias is removed seriatim from each tube 1, 2 and 3, and each condenser 35, 36 and 37 for each such tubes 1, 2 and 3 will discharge through their corresponding potentiometers 40, 41 and 42, according to the setting of potentiometers. This triple contact relay 33, while operating the points, simultaneously has the etect of causing the tubes 1, 2V and 3 to fire in, series,v due` to the various settings of their re` spective potentiometers 40, 41 and 42.

Specically, tube I res whenits grid voltage reaches the critical' point. Current thenilows from tube 1 through lead 49, resistor 50, to relay coil 12, energizing the sameI andi closing*4 its; normally open contactor or switch 52, thereby applying 440 volts to solenoid controlled air valve 51"; (the coil or solenoid thereof only being shown in this electrical diagram). When solenoid 51 operates in the die casting machine, it operates a two-way air cylinder., 332, which through the linkages showin, turns the lever 83a; turning the main four-way air valve 84a'. to the. position of Figure II. Referringto Figure; 11 this, connects the. airA supply around a check valve;A and; throughthe by-pass 142a only to move piston 32a:of;the.- second or air motor 32 slowly at the first portion of, the metalt injection.

'Iube 2, operates, in aY similar manner to supply current. to relay 11;,rst operating itsy switch and then the air: valve coil 61; Thisair valve coil or' solenoid 61 controls the supply of air `to the controlling means or valve.. 61a; shown. in.Figure; IH, turning valve 61aV to thc positionshownf in Figure. III. This opens the check valve as.shown. in thisY figure andremoves its checking effect on the,.maintope ration.of the casting machine, and now the main step of injecting the. metal quickly is accomplished by the machine.

Inviewfof. the fact that both tubes 1- and 2 have now tired, atpressure, is. held on the metal in the die for a certainlengthrof. time, whichisvery importantxin this die casting ,machine.` This,I pressure on the metal with the dies closed is held until tube 3 fires, which removes this as will-i now* ,be s described.

Thyratron.- tube?, 3l is interconnected in the system througlgr.relayerA 70.` so that when tube 3 tires, it again changes.'` the controligrids'of tubes 1 and 2 back to bias position.. Tube. 3has.itsltime,delay- (through condenser 37, ptentiometer- 421. hereinafter described, and this aetiomholdsthe-pressure; on theldies, as just stated. Firingpof tube 3ahas, the-.effect of releasing or deenergizing both; coilstSl. and. 61' andtheir corresponding air'valvcs, andgthe machine: partstare mechanically returned to normal., Thus, uponiiringf tube 3 (when relay 33 has actedy as.I statedifaboye), currentilows through the coil of-relaycontactorltliand closes the twoinormally open switches 71 and 72 and opens the one normally closed switch 73; Thertwo-closed'` switches now operate to reappniygbias,- to,tubes;1. and 2 .which Ibreaks their Aplate circuitajand,deenergizes-relays, 11i-.and 12 and thus removes the440..volts from. the two air valves 51 and 61. Actually, in;the-,di-e; casting,machine at-ithis point, the ar'valve 51 hasthe double, function of` now causingr the lever 83a-.ztof-,be-turned-.back to'fnormal. positiorrallowing the the-othenside thereof.` In=the.meantime, releasing'air valvefl; has reset'the check valve previously referred to ascontrolled-by,;tube.2;I

Current input circuit Theamaminput circuitleads :90,191 .and 92 of the three phasqq 440-.volt,;input=,circuit!are shown-on the draw ing,;,the-.leamz92 beingconnected to the operatingmotor .95;as-willihereinafter, be described` Iand set forth. The

leads..90and;-91 arethe two ymainleads for-supplying the ;cunre'ntf.to ther-electrical control system for the die casting-machine.

This supplies A. C. energy to the transformer 100,

rwhich reducesthewvoltageon two secondaries to and 220, respectively. The lead 102 for the 220 volt circuit extends from the secondary 101 .to the point .of time delay relay '1 0'3, 'the point being designated yby the numeral 104. `This point -is normally open. Upon energizing rei v'1ay 1`03, .this point 'closes and connects lead 102 through lead 106 for the 24 volt control circuittr'ansformer 107. This transformer 107 has a lead 111 whichv is connected lead 1 12 and lead 113 through safety switch 22 to the relay 20 described above. When the automatic' starting 'switch `zit is closed, this energizes therelay 2 0, as indicated supra. For' the purpose rof energizing `c oil 20, a lead 115 is connected with lead 113 and through 'auto'- niatic closed button 23, lead 117, through a' lead, to 'the relay a's shown. The return circuit starts from relay 20 through lead 119 and is connected to lea'd 120, whichV returns to the other side of the transformer 4107. This circuit, however, is merely a momentary circuit, and it requires the 'operation of a `hold circuit to actually contol the relay 20 which will be hereinafterde'scribed.

For controlling relay 10, the control voltage `is applied 'to the 24 volt coil 20. When 4the button 23 is pushed, voltage is applied vacross the relay 20, enrgiz'ing the relay and causing the bias to be shorted out on tube `5, as indicated above, which causes the tube to fire after a short time delay due to the condenser 25 and resistor 26. This operates the relay 10 and its switch, which supplies 440 volts'to the main oil valve coil 30 causing the machine to close. V

The microswitch 27 is normally open, but is closed by a machine operated part when'the machine locks up' which is done mechanically as in the prior patents above referred to-"and 'closing microswitch 27 thereby applies voltage of 24 volts to relay 33;

Transformer 170 supplies 6.3 volts from secondary 171 to the lamentsof each thyratron tube 1, 2, 3, 4 and 5 (circuit notshown).

lAnother secondary 1 72 of transforrner 170 supplies 5 Volts to the filament o f rectifier tube 173. Another secondary 174 supplies voltage to plates of rectifier tube 173 through leads 175 and 176, as shown. A center tap 177 is connected to a filter condenser 180, the other side of Said filter being connected to ground lead v133. This center tap 177 is also connected to resistor 181 connecting lead 182 to relay coil 103'. The other side of coil 103 is connected by lead 183 to regulator tube185 cathode, the anode being connected to ground lead 133.

Bids suppl-y for tubes 2', 3, 4 1nd 5 Tube 185 maintains 7.5 volts across it despite variations in supply voltage. Lead 183 also connects to lead 186, y'which is the main bias supply lead for all the thyratron tubes 1, 2, 3, 4 and 5. Specifically, this is arranged by `providing a set of iilter's for each tube, excepting tube 5.

For tube 1, we have shown connected from lead 186 a iilter, consisting of a resistor 190, condenser 191, connected to ground lead 133 and between the two at point 192, there is a lead 194. This lead 194 is connected with point h195 on relay 33 and point 72 of relay 70. The other side of point 195 is connected by lead 196 to the control grid of tube 1. Lead 196 is also connected to the normally open point 72 of relay 70. This control grid is the itrigger action for tube 1.

The filaments of each of tubes 1 to 5 is supplied with `a 6.3 volt circuit from the secondary 171 of the bias transformer 170. i

`In operation oftube 1, the point 195'of relay 33 being normally closed, the bias supply through lead 186,- -resister 190, from point 192, lead 194, point 195,- lead 196, charges the condenser 35. When the bias is removed, as will hereinafter be further referred to, the point V195 opens by yreason of the action of relay 33, and consequently, the condenser 35 will then discharge through the potentiometer 40 and a controlling resistance 200 to the ground lead 133. This resistance 200 is to limit the iiow of current when the potentiometer is set at zero, which 6 would otherwise draw too much current from the bias supply at 192 and might ruin thepotentiometer 40. p

The 'bias for tube 2 is identically arranged as described in connection with tube 1, the corresponding resistorand condenser having the connection 201 for lead 202, which is connected to point 71 of relay 70, point 71 having lead 203 for connection to the control grid of tube2, the timing circuit for tube 2 being by way of condenser 36 and potentiometer 41. We also provide a limiting resistance, such as 200 for tube 2.

The bias for tube 3 is from connection 205, through lead 206, to normally closed point 207 of relay 33, lead 208, to the control grid of tube 3. Tube 3 also has a timing circuit similar to that described,`supra, as to tubes 1 and 2 by way of condenser 37 and potentiometer 42.

The bias for tube 4 is from connector 210, lead 211 to normally closed point 73 of relay 70, lead l212 to the control grid of tube 4 which also has a timing circuit similar to that of tubes 1, 2 and 3, but by way of condenser 45 and potentiometer 43. The firing of tube 4 will be hereafter set forth. v

The bias for tube 5 is from the main bias lead 186 through current limiting resistor 215, lead 216, lead 217 to normally open point 24 of relay 20, lead 216 also being connected through time delay resistor 26 to the control grid of tube 5.

The firing of tube 5 and removal of the bias loccurs when normally open point 24 closes by reason of the action of relay 20. When point 24 closes, the lead 217 becomes a ground connection, sincepoint 24 is now connected through lead 220 to ground lead 133.

When relay 20 operates to close point 24, then the condenser 25 for tube 5, which is holding the voltage on the grid of tube 5 due to the charge of condenser 25, discharges through resistance 26, lead 216, 217, point 24, lead 220, to ground 133.

The operation of tiring of tube 4 which has the effect 4of opening the casting machine will now be described.

To do this, since tube 3 has fired, the biasvsupply has been removed from tube 4 (after the time delay, through potentiometer 43 and condenser 45 has taken place). Thisenergizes relay coil receiving energy through lead 130, which has 220 volts A. C. being connected to point 104 of relay 103. The other side of relay 80 has lead 131, resistor 132 to the plate of tube 4. The cathode, which is the return circuit of tube 4, is connected by lead 133 to ground 134.

Relay 80, having now been energized, opens normally closed point 81 which is in the holding circuit for relay 20 coil. This removes current from relay 20, allowing it to deenergiz'e and open point 21 and point 24, which restores bias to tube 5 and, hence, deenergizesvoil valve solenoid 30 which operates valve 63a or the main oil valve for the mechanical means orhydraulic motor and eiiects an opening of the dies, as will be understood.

As a safety device, we also have a control, so .that if any air is on the main air cylinder (which. injects the metal) the dies cannot open. To do this, we have an air pressure operated switch connected from point 21 by lead 141 to one side of 140. The other side of switch 140 is connected by lead 152 and to lead 118 to, relay 20. This puts switch 140 across relay point 81 and prevents the holding circuit from being opened or broken asv long as there is air pressure in the upper side of the main air cylinder.

We also have a further controlso that with certain dies necessitating the cores being removed before the die is opened, the machine will not open but shows a light so that the operator may time his operation and actually remove the core before the machine is opened. To do this, we use a double pole manual switch which maintains, when closed, voltage on relay 20 even though relay A80 would have otherwise opened 20 as when tube 4 tires. To this end, we provide a set of points 151 for switch 150. Lead 118 connects to 151 through vlead 152, and

, 7 r t the other side of switch 150 is connected by lead 153 to lead 141 to point 21 of relay 20 (hence to supply circuit).

The pilot light circuit (controlled by switch 150) is as follows: 110 volts from supply circuit lead 160 is connected to point 82 of relay 80, lead 161 to pilot light 162, lead 163 to switch 150. The other side or point 155 of switch 150 connects with lead 164 to ground lead 133.

We also provide a manual circuit whereby the machine may be manually operated in conjunction with the foregoing, and in this connection we provide a switch 225 arranged to shift the circuits from automatic to manual control. Thus, switch 225 is connected with input lead 90 having a lead 225. In the drawing, the switch 225 is shown in the automatic connection with the point 227 closed to transformer 100. This shift over switch 22.5 has a point 228, said point 228 connecting the input lead 90 with lead 226. When it is desired to use the machine manually, the switch is closed to the point 228 which is normally open and also to the pilot light circuit. The lead 226 also connects through lead 230, resistance 231, to the pilot light 233, resistance 234,'return lead 235, connection 236, lead 237 to the other input supply lead 91.

The coil 229 has a lead 240 connected with normally closed push button switch 241, lead 242 and switch 245. The other side of the switch 245, which is open, is connected by lead 246 to the return lead 235. By closing switch 245 manually, the coil 229 is energized because a closed circuit has been established to the input and output main lines 90 and 91. When this is accomplished, point 228 closes and applies 440 volts across the oil pilot valve solenoid 30 for the main casting machine connection. When the relay 229 is energized, it also closes the point 247 and establishes a holding circuit for coil 229, by reason of connection 242 to lead 243, to point 247 which is now closed, and lead 248 connects the same to return lead 235 which brings it to lead 91.`

When point 228 of the relay 229 closes, a lead 250 connects the same with coil 30 of the oil valve solenoid, it being understood that the main input circuit from lead 90 connects through lead 226 to the point 228 as well as the coil 229.

The main leads, relays, connections and controls of these various circuits of Figure VII have thus been specifically described and the principal elements thereof numbered on the drawing in Figure VII, practically every lead and part being numbered so that exact circuits including all the lead connections therefor may be readily traced on the drawing.

We also provide circuit arrangements for connecting the power line to the motor of the machine, which builds up the oil pressure for operating the machine. Moreover, these circuits control the connections for the main input supply lines 90 and 91. To this end we provide a push station 260 interconnected with the three leads 261, 262 and 263. These three leads are diagrammatically indicated as push station leads from a magnetic starter (not shown) which connects the main outside power lines to the leads 90, 91 and 92.

Emboa'ment illustrated in Figure VIII We show in Figure VIII a further and preferred ernbodirnent of our invention.

Transformer circuit (from input leads 90 and 91)- Fgure VIII -manual switch 454 establishes the main power inletconnection to the control system to be described while switch 443 of contactor 442 hereinafter described supplies voltage from the power line for operating the main solenoid 30', 61 and 51 for the actual operation of the machine. Then, by leads 461 and 462 voltage is applied to a main tapped transformer 465 which has a 440 volt primary and a 220 voltage secondary tapped at l1() volts to give another or third reduced circuit voltage of 110 volts. A circuit ground lead 467 is grounded at 468.

We provide a 220 volt circuit from transformer 465 (said circuit to be hereinafter further described), for the purpose of supplying current to the plates of thyratron tubes 1, 2, 3 and 4, and also through an additional transformer 482 to the 24 volt control circuit for actually connecting the operating circuit to the machine control valves.

In Figure VIII, the diagrammatic connection illustratn ing the control circuit includes the automatic return push button 640 which, being connected to the power, closes the circuit through the microswitch 603 and lead 400 to coil `402 to close its contacts so that the casting machine dies close, as in Figure I, relay 402 being the key relay for controlling the die operations in the embodiment of Figure VIII. Lead 405 extends from switch 401, lead 405 to relay 406 having normally open switch point 626 onthe power panel and connected with the input circuit as will be hereinafter pointed out. Then, a lead 407 extending from the other side of relay switch point 626 connects with relay 10' causing an operation of the valve 30 and hence effects operation of the die actuating mechanism. The other side of this circuit from coil 10 is by lead 410, point 625 of relay 406, hence, by lead 409 and lead 408 to main power switch relay 430 (the input circuits to be described).

The 24 volt circuit closed to relay 10' (during the operation of the machine), energizes coil 30 to close the die operating mechanism, the circuit for coil 30' being a 440 volt circuit from the power line.

Tubes fire in sequence, effecting casting machine operation Following the operation of said die closing circuit controlled by relay 402 in Figure VIII, the thyratron tubes 1, 2, 3 and 4 fire as in Figure VII. Tubes 1 and 2 control the metal injection in two stages. Tube 3 temporarily rebiases tubes 1 and 2 and tube 4 resets the circuits to initial position, rebiasing all tubes. Thus, tube 1 res, causing slow injection of molding metal as shown in Figure Il; then tube 2 firesreleasing the main valve retaining means of check valve mechanism 142a to permit a full shot of metal as in Figure III; tube 3 provides a time delay after tubes 1 and 2 have fired, and then when tube 3 fires, it resets tubes 1 and 2 (releasing their valves); when tube 4 tires, it unlocks die closing mechanism, allowing dies to openall as will hereinafter more fully appear.

Power input circuit- Figure VIII The 3 phase inlet leads 90, 91, 92 are for a standard type of three phase motor 95', the motor which produces the oil pressure for the die operating mechanism and includes a branch lead 441 (from input lead to a standard type of contactor shown indicated at 442. Another lead connects 91 with contactor 442. A standard type of push station mechanism 443 is used to energize contactor 442, thereby applying power to motor 95 and also supplying 440 A. C. volts to coils 30', 51 and 61, the controlling relays 10', 11 and 12 being ou a 24 volt circuit.

A safety feature is here provided, in that if contactor 442 for any reason opens, it removes the power from the main injection operating air valves 51 and 61 and oil valve 30', thus preventing squirting metal into the room. To do this, we provide power leads 445 and 446 in these coil circuits, lead 446 passing through the points of contactor 442 as shown. Thus, if contactor 442 is opened, then no voltage will be applied to coils 30', 51 and 61 because the operating circuits to said coils will be opened.

Tube supply circuits, transformer connections, etc.- Figure VIII We also provide a 110 volt circuit `from a vmain transformer 465 (said circuits to be 'hereinafter further described), to supply another transformer 475 for lighting the filaments of tubes 1, .2, 3, `and 4 at 6.3 volts and another circuit for a heating element. We also include a 5 volt heating element for al rectifier tube 553 and a high voltage for the plates of the same. This rectifier tube 553 supplies D. C. current to the grid bias circuits for the main thyratron tubes 1, .2, 3 and 4.

The 110 volt circuit from main transformer 46S includes fuse 469, lead 470 to normally open point 471, lead 47.2 to connecting point-473, which supplies, through lead 545, the 110 volt primary of vtransformer 475. The 110 volt circuit from main transformer 465 also has lead 476 connected to lead 470 vfrom said transformer, said lead 476 extending to Vterminal 477 to supply lll) volts for gas supply and heat control.

Referring now to the above'mentioned 220 volt circuit from transformer 465, the same includes fuse 480, lead 481 to primary of transformer 482. The other side of the primary of said transformer 482 is grounded at 468 through lead 483.

This transformer 482 has a 24 volt secondary Winding with lead 484 which, by lead 487, passes through a coil 406, the other side of coil 406 having lead 488 connected to switchA 491 (normally open). The return circuit includes lead 493, and lead 485 to the other side of the 24 volt transformer 482. Thus, when switch 491 in this circuit is closed, coil 406 is energized and'this closes switches to effect an application of voltage to the system Ifor automatic operation of the machine. Therefore, switch 491 is a key switch by means of whichvthe mechanism may be disconnected from all automatic operation and, in certain instances, the machine may be `operated manually.

This .24 volt control circuit also connects through lead l484, and a' short lead (not numbered), to both points 495 and 496 of relay 430.

Relay 430 is located in an arrangement of circuits provided to give a delaying action to the application of the 220 volts to the plates of the main network thyratron tubes 1, 2, 3 and 4 to allow said tubes to warm up. This 220 volt plate circuit is also controlled 'by the main bias for saidtubes through coil 499 ashereinafter set forth, but the delayed warm up control' action'is accomplished by a mercury time delay mechanism 499, 499 and the connections are controlled by relay 430. Thus, this 24 volt circuit is connected from transformer 482 by lead 484 to lead 497 through point 499 of the combined choke coil and relay 499 and back by lead 498 to the coil of relay 430. The coil 430 is connected on the other side by lead 485 to transformer 482.

Each of the plate circuits for the tubes are connected to ground terminal 468 from the main transformer 465, since each cathode circuit is grounded as shown. On the other side from said transformer 465, the Vplate circuits include the fuse 480, lead 500 to normally open point 501 on relay 406, which point is closed inthe automatic position of the apparatus. From point 501 we provide lead 502 to normally open point 503 onrelay 430, which point is also closed in the automatic machine position but only after the time delay for the tube warm up has taken place-in view of switch 499', supra. Lead 505 from point 503 connects with lead 506 and all the tube place circuits connect to wire 506. Thus, for the plate circuit of tube 1, We have a lead 507 connected from lead 506 to resistor 508 to limitthe current iiow,

lead 509.*tocoil `510 and lead 511 yto the plate of-tube 1. The 'cathode circuit o'f Ytube 1 :is grounded vas "nditil by acircuit 51'3 and, hence, completes vthecircuitgte finie main transformer 465, since lthe'lat'ter is grounded at 416,8, as stated supra. We also have a condenser 512' coni nec'ted across -coil .'5'10 to supply current to :therelay :coil 510 on the negative one-half cycle and prevent chattering of the ypoints controlled by .relay 510.

Theother tubes 2, 3 and 4 aresimilarly connected.

Thus, .for vtube .2, lead 514 is connected -to the Ilead 506 common to allof ,tubes 1,2, 3 and 4, as indicated supra, 506' beingconnected with .506 Aas shown. Lead 514 connects through resistor 4515, lead 516, tto edi15'9f6, hence, by a tlead '517 to the plate of tubeZ as shown. A condenser 51.4 is connected across leads `516 and for coil 596 as shown.

For connecting tube 3, we Aprovide a lead 520 passing through the resistor 521 'to :lead K522, whichconnects with coil 600 having .lead Y524 yconnected to t'the .plate of tube 3. A condenser v525 ris connected across'leads 522 and 524. The cathode circuitof tube 3 isgrounded as indicated by circuit 526. y

For tube 4, we also provide .a lead l530 connected ,with a common connecting lead 506', limiting resistor 531 lead 532, coil 412, lead 131, to the .plate of tube 4. We also `provide a condenser 535 across .leads 532 .and '131:as in the case of the other three tubes. Thecat'hode of tube 4 is also grounded lby circuit 537, yas indicated.

Bias circuits The bias supply for each of tubes 1, '2, 3 and 4, rwhich is from a common source toeach tube, will now be Vdescribed. I,

volts from the main transformer 465 'through relay 406 connects by lead 472, to terminal 473 Which is connected bylead v545 to the primary of the 'traits- .former 475 Aand returns by 54'6 5to ground as ys'lswnaft 547.

The transformer 475 has three secondaries, one 5,550 .for the 6.3 volts for the filaments of the tubes 1, 23 and 4. Another secondary output circuit of 5 volts .is indicated 551 for the rectifier tube 553. Y

The third secondary from transformer 475 constitutes ja source for supplying the bias for 'the several 'thyaton tubes 1, .2, 3 and y4. The current for Athe biasi's changed .from alternating current lto D.C., and, to this eiidwe provide rectifier tube 553 connected by leads 552 ,and

'552' joined on the outside terminals of Winding 5454 transformer 475 and to the plates of rectifier tube 553 as shown. The cathodevrof rectifier tube 553 is grounded. Parallel to the plate cathode circuit of rectifier tube 553 is a condenser circuit 558 having a filter condenser 559 located therein. We also provide in the grid circuit for the main thyratron tubes a voltage regulator' tube "561 grounded as shown so that the D.'C. current from fthe rectifier tube 553 is supplied to the plate of regulator tube 561 as indicated. The outlet terminal Aof regulator tube 561 is connected by lead '560 to lead 563 Fand also to lead 565 which is the main bias supply leadffor .the thyratron vtubes 1, 2, 3 and4. We also provide -a bleeding resistor 562 in a circuit parallel Atojthe regulating vtube 561 as shown, connected with l'the ybias supply lead 565.

The relay and controlling coil 499 is connected by va lead 560 to the output lead 560 of the regulating lube 561, said coil 499 being also connected by lead 557 through resistor 556 to the center of winding 554-which places coil 499 in series with the grid circuit -for the thyratron tubes 1 and 2. l

Our connections for these tubes also forms atime delay for the warming up of tubes 1, 2, 3 and 4, since relay 499, when energized, closes points 499', there vbeing `ya time delay on the make of said points 499 with a well known type of switch which has a quick break.

Moreover, this relay 499 provides asafety arrange ment, since fanure of Iany par: of the bias supply will 1 1 cause 499' to open, dropping out relay 430 which disconbeets the plate circuits of the tubes 1, 2, 3 and 4. 'I'his also drops out the 24 volt control circuit to the automatic operation.

Connections for the bias supply voltage and tubes 1, 2, 3 and 4 The above circuits and the tubes 553 and 561 provide means to produce the bias voltage for the main thyratron tubes 1, 2, 3 and 4. We will now describe its connection to thesetubes. Thus, we have a main bias supply lead 565 joined to lead 563 as shown, which lead 565 connects with three points (normally closed) on relay 566, points S67, 568 and 569. Lead 565 is also connected with the points of relay 600, namely, points 570, 571, 572 and 573. This lead 565 also has a connection to lead 575 to a contact 576 of relay 510. Lead 565 is in the main bias supply line for all four tubes.

' For tube 1, bias is normally supplied from lead 565 to' point 567, lead 577, resistor 578, the lead 579, to the grid of tube 1.

I :Fortube 2, the main bias is from point 568, lead 580, resistor 581, lead 582, to the grid of tube 2. This main bias lead 56S also has a connection for an auxiliary circuit "for tube 2 by lead 575 to a contact 576 of relay ,510 controlled by tube 1 since lead 590 from point 576 is' connected to lead 580. For tube 3, the main bias includes lead 583 from lpoint 569, to resistor 584, lead 585, to the grid of tube 3`.

,t TubeY 3 also has an auxiliary bias circuit, since we proyide, as more clearly shown in Figure VIII, a lead from .bias line 565 to point 572 of the relay 600 as shown. We also provide a lead 572 from point 572 to point 595 'of relay 596,0ftube 2. Then we also provide a lead 595 connecting with lead 583 to the grid of tube 3. Hence, the auxiliary bias for tube 3 is so connected as to have in series -therewith a switch controlled by the relay for itube 2.l

For tube 4, the bias includes a lead 587 from point 573` to resistor 588,*lead 589, to the grid of tube 4. As the necessary part of. the operation, as will hereinafter ,appear more fully, we also provide additional temporary 'Ibias circuits for tubes 1 and 2. This additional bias for `tubes 1 and 2 includes a circuit from switch point 5'70` of relay 600 by way of lead 570 which connects to lead ,577 to the bias of tube 1. For tube 2, this additional .temporary circuit is connected with relay point 571 by lead 571 vwhich connects with lead 580 to the grid of tube 2. i

, Sequential firing of tubes We have provided means for causing tubes 1, 2, 3 and 4 to tire in sequence one after the other, and, moreover, any subsequent tube in the series cannot re until ythe preceding tube has fired. The circuits and means for 'accomplishing this will now be described. Thus, when relay coil 566 is energized, this opens points 567, 568 and 569, removing the main bias from tubes 1, 2 and 3. However, bias for tube 2 is now being supplied through an `auxiliary circuit including a connecting lead 575 extending -from lead 565 to switch point 576, lead 590, lead 580,

resistor 581, lead 582 to grid of tube 2. When tube 1 lfires (at the end of its time delay, to be described) relay Firing of tube 2 At the expiration of the time delay for tube 2, tube 2 jres.(the auxiliary bias being removed by tiring of tube 1, as statedsupra).-

The bias now on tube 3 is by reason of the auxiliary bias circuit described above. Firing of tube 2 opens normally closed point 595 of relay 596 which removes this auxiliary bias from tube 3.

The energizing of coil 596 also closes normally open point 597 which, through lead 59S, energizes relay 11 for operating the check valve mechanism 61 to give the full shot of metal used in the die casting machine.

Firing of tube 3 Removing bias from tube o allows tube 3 to tire at end of its time delay energizing the coil of relay 600, closing normally open points 570 and 571, thereby rcapplying a third or temporary additional bias to tubes 1 and 2, thus resetting these tubes and their associated plate circuit relays.

Firing of tube 4 Moreover, normally closed points 572 and 573 are opened and since 572 is opened, this prevents reapplying bias to tube 3 by tube 2 at this point of the cycle. The opening of 573 removes bias from tube 4.

When tube 4 tires at the end of its time delay, the relay 412 is energized, opening normally closed point 413 which breaks the holding circuit for the die operating mechanism above described. This holding circuit being removed, coil 30 is deenergized, and this permits the dies to open by a spring X thereby shifting oil valve 63a (see Fig. Vl) and reversing the movement of piston 60a causing the hydraulic (trst) motor through the linkage and associated mechanism to cause return of the die B to open position.

T me delay circuits for tubes I, 2, 3 and 4 For each of tubes 1, 2, 3 and 4 we have a time delay network for the bias circuits thereof which includes lead 577 (bias supply lead for tube resistor 57S), lead 579 to grid of tube 1. Before normally closed point 567 opens, there is a circuit through resistor 578, lead 579, which also charges condenser 660 which, until the bias is removed, supplies a voltage to grid 1. However, when switch point 567 is opened, condenser 660 is discharged through adjustable potentiometer 661 (which may be variably set by the operator) and current limiting resistor 662 to ground 513 as shown. The other side of the bias circuit and tube cathode is grounded as described supra. Thus, the setting of the adjustment on potentiometer 661 determines the time for discharge of condenser 660 which, when it reaches critical grid voltage of tube 1, allows the tube to tire. Resistor 662 limits the current to a very low amount offsetting the potentiometer 661. Resistor 578 has two purposes, one to prevent main bias supply from being shorted in case condenser 660 fails. Also it provides a buffer action to prevent burning of point 567, due to sudden inrush of current to condenser 660. lt will be uderstood that we have provided similar potentiometer time control discharge networks for each of the other tubes 2, 3 and 4 and in the drawings we have used the same numerals as for tube 1.

Reapplyng bias to mbe 3 The bias control of the tube 3 (and also 1 and 2) is interlocked with the microswitch 602 which switch, iu turn, is actuated by the rack or part of the linkage for opening and closing the dies of the machine, which rack is operated by the hydraulic system including the motor and its piston 63a for the die operating mechanism. The microswitch also has point 603 (normally closed). Closing of point 602 by said machine operated part closes relay 605. This is accomplished by circuits connected with the 24 volt control inlet power relay 430 which includes lead 408 from contact 496 of relay 430, aad leads 409 and 606. Another lead 607 also connects from lead 606 to a point 608 (normally open) of relay 412. On the other side of coil 605, a lead 610 connects with normally open side of microswitch 602, referred to supra, and lead `3 61.1., leeds .6.5.2, 424 .and 425, normally .open ,-point 4.2.6 of relay430- When .coil .605 Iis energized, .coil of relay 566 ,is also energized. Relay ,605 has threenormally open jpoints 612,;.613 and 6,14. The connection from relay 605 to relay 56,6 includes point ,6j-12, ,lead 61,5, lrelay coil ,566.

From the fother side 'of relay 566, lead.616 .connectsto lead 411,9, point 418 rof relay .40.2, .the .other side of the :switch 418 .has Aet lead I41.7 r.extending yto .terminal .416, hence, by `lead 6.18 `to Safety point i619 normally closed) of a switch associated .with normally .open button starter switch.6,40 and `said switch point `6.19 `also `-connects to lead 6.20 and connection 62.1, ylead Y.6.2.3, which connects .to lead y606 completinethe .circuit for energizing .coil 605 and., hence, coil 5.66.- Energizing coil 5.66 opens `all three points 567, 5.68 .and 569, which removes bias `from ,tube land allows the biasV to 'be removed in sequence from tubes 2 and 3, andthe bias to tube 3 is reapplied by point ,56.9 of relay ,566 when relay 566 is deellergized as the machine opens by breakingthe microswitch at point 602. In .the meantime, bias on tubes land -2 has been restored when tube Stilles, as stated supra.

Pressure switch control for preventing machine fromopening7 when metal is being injected into dies We provide a Specialsafety control in connection with preventing metal injection when the dies are open .and valso on improper action in casethe operator accidentally presses a control part.

Thus, .from relay 406 (to which .current is supplied from ltransformer 4.82) we .provide a-.circuit .from point A62.5 of relay .40..6to .a pressure ,Switch 623 by leads 409, 408, 651, 652, 424, point 613 of relay 605, lead 629, to .pressure .switch 628. This pressure switch '628 is located across the die open and closing control circuit in such a way as to. prevent the machine opening, but cannot accidentally close it. When the lmachine is in automatic control position, relay 430 is energized thereby closing Points 49.6 and points 42.6, as statedsupra, and 24 volts is supplied through points 496, lead 408, 409 to normally open point V6 25 on relay 406 and in the automatic position, this point 625 is closed, allowing current then present at point 62,5 to pass through lead 410 to coil of relay 10', hence from the power line to coil 30- The other side of relay 1 0 by lead 407 connects with a normally open point 6.26 of relay 406 (closed in automatic position),'hence by leads 405 and 62.7 to the pressure switch as shown and lead 629 to point 6,13 iof relay 605. From relay 605 the other side of 6,13 connects by lead 424 and lead 652 to return control voltagelead 425, point 426 of relay .430 supplying energy at l24 volts from transformer 482.

Point 613 on relay 605 is primarily for connecting pressure Switch 628, which 11s `an electrical contact on a pneumatically operated mechanical pressure switch in such a manner that the pressure switch,` while it may hold the machine closed as long as air pressure exists on switch 628, yet, if air pressure is -supplied accidentally, such actionrwill not result in theclosing of machine from an open position since relay 605 must be energized to vhold point `6,13 closed before the pressure switch can be effective to Supply energy tothe coil 1,0 (die closing)- If switch point V613is open, such connection will be broken. The microswitch point 602 .controls relay. 605, and the machine must be closed before 605 is energized. Hence, if the-machine is not closed, 605 is deenergized and point 613 is open so that no energy can be supplied'to coil 10.

Hence., We have provided not only a dual safety control which will render inoperative the metal injecting means yif not in the correct position of one or the other of its twofposition locations, since not only must the microswitch be in correct position but the pressure Switch 6 28 is connected in series and,` therefore, simultaneously controls the action of the machine to prevent opening of 14 the V:dies if the metal injection .controlling means is .in .abnormal condition. y

Circuit to prevent :relays *1,1 vuna! 12 from` contacting :until dies areclosed `Whenrn`icroswitch `6,02 is closed, .this energizes relay 605, and( hence, closes points612 and 613 and 614 as /indieeten supra. `When point Y614 closes, we have a safety circuit from point `.614 whichis conected .on one side to lead 424 to 24 volt tcontrol circuit. From relay 605 at the other side of point 614, we provide a lead 63S which connects to ,relay coils 11 and 12 in series.. Referring gto coil 11, we have a lead 598 connected to point 597 of relay 596, ,through said point 597, leads 409, 408 to .the other side ofthe V24 volt circuit at point 496 or relay 430.

This safety circuitjjust described, also controls relay'lZ.

'Thus from lead .635 (for relay 11) we also have a Vlead 636 to relay 12, and from relay 12 by lead 637 we connect to point v592 of relay 510 through point to lead 408, hence to point 496 of relay 430.

Thus, it 'will .be seen .that both relays 11and 12 are interconnected .in the 4system so that these relays cannot be closed when the dies are opening, since relay 605 would be open, and `hence point 614 would be open and break the circuits for both relays 11 and 12. Thusif tubes 1 or 2 fired, dueto a fault, then relays `11 and 12 would not `operate to inject metal ,into the dies if open .and hence into the room. v

. Microswitch must be in correct position We have a further circuit to correct a condition when in operation microswitch 603 becomes yjammed iny the other position 602 Yin which position the circuits would cause an injection of metal into the die. This additional circuit acts as asafety circuit to prevent such an improper. injection of metal in case operator presses close .button 640. When operator presses close button switch 640ofthev switching connections indicated at 23 to start an automatic cycle of the machine, the circuits include safety switch k619, starting switch 640, lead 641 through safety point 603 of the microswitch, lead 400 to coil 402, which completes the closing circuit forcoil 402, and this closes the machine. However, it will be seen that if point 602 is in metal injecting position, or ink an abnormal position, the operator will not be able to close the machine, since point Y603 would be open if the microswitch is not in its normal position for the start of the cycle.

Sfety circuit to prevent mtachine operation by accidental closing of microswitch If point 602 of microswitch is closed accidentally, un less at correct normal position, relay 402 has not been energized leaving point 418 normally open. Relay 566 and associated points 567 and 568 are actually the controlling lpoints for the two stage metal injection through coils 11 and 12. Thus, if microswitch is accidentally closed,causing relay 605 to close, which would otherwise start the metal injection cycle, relay coil S66 will not be energized even if point 612 of relay 605 has closed, because the other side of coil 566 has its circuit broken, by normally open point 418 which will not be closed unless machine is in normally operating cycle by action of the automatic close button 640'. The manually controlled automatic station and the microswitch control circuits are therefore dependent upon each other as indicated.

Emergency switch` for stopping automatic actionV and causing machine to open and mechanism torbe reset In the automatic operation of one complete cycle of the machine, the relay 402 acts as an electric self locking in means for effecting the supply of current to the various circuits heretofore described. As will be seen from Figure VIII and the foregoing description, this current supply, as stated supra, is a 24 volt circuit which includes lead 620 on one side and 424 on the other (traced in detail below). We also provide, however, an emer- 15 t gency switch 619 which is normally closed, but which may be opened to break this locking in circuit. Referring to the drawings, this is accomplished as follows:

The.24 volt circuit referred t ows from lead 620 through the normally closed, momentary breaking, safety button 619, through lead 618, point 416, lead 417, to relay 402. This relay 402 is energized when the machine is operating in which case point 418 of this relay 402 will be closed. Thus, current from lead 620-417 passes through point 418, lead 419, to point 413 of relay 412, through this point, through leads 415 and 400, to the coil of 402, back to lead 424, which is the other side of the 24 volt supply. Since the locking in 24 volt circuit for relay 402 is supplied between the leads 424 and 620, and this emergency safety button type of switch 619 is interposed between these two leads, it will be seen that when the operator opens the switch 619, the locking relay 402 is released and the metal injection cycle resets and the dies of the machine open.

Pilot light for heat control instrument We also have a heat control pilot light 645 in a circuit from the 24 volt transformer 482 connected on one side through leads 484, 486, 497, light 645. From the other side of light 645, we have a lead 647 to terminal 492 and lead 493 and 485 to the otherV side of transformer 482. Moreover, we provide an interconnected network so that when the heat control on and off switch 454 is closed (which is a toggle switch) it energizes relay 456 through leads 459 and 460 applying 440 volts to `transformer 465 (primary) to supply 110 (secondary) for the heat control motor and gas valve `(not shown). This energizes transformer 482 from the 220 secondary of transformer 465, which supplies 24 volts to the pilot light 645 through the circuit just described supra. Therefore, when switch 454 is closed, it applies 24 volts to the pilot lamp 645 showing the operator that the heat control and gas valve section of the network is on. Relay 456 has a transformer 457, the control circuit of which is 24 volts supplied by said transformer from the 440 volt circuit. This avoids the necessity of supplying 440 volts at any time to the control section of the network.

Pilot lamp for indicating machine ready for Automatic Action We also provide a lamp 650 connected by lead 651 to lead 408, hence to point 496 of relay 430. On the other side, lamp 650 is connected by lead 652 to lead 425 to point 426 of relay 430. Operator closes switch 491, thereby energizing relay 406 throwing the circuits into automatic position. This energizes bias circuit transformer 475 and connected circuits, which at the end of a time delay (allowing tubes 1, 2, 3 and 4 to warm up) closes point 499 of relay 499 energizing relay 430. This applies the 24 volt control circuit across the pilot lamp 650 and also supplies 24 volts to the automatic .control section and, hence, shows the operator that the tubes 1, 2, 3 and 4 have been heated suiciently for operator to close button 640 to start machine in automatic operation, but there is no control voltage on the automatic section until this above-mentioned time delay has expired.

Manual control circuit We have a manual automatic switch 491 that is for r shifting from manual to automatic or automatic to manpoint. 495 (relay 430) and by a lead (not numbered) to 16 lead 484, to other side of control transformer 482. Thus, when the mechanism is in manual position, determined by the position of switch 491, and switch 665 is closed, 24 volts is applied across the coil of relay 10,`operating the solenoid for oil valve 30 to close and open dies of machine but the rest of machine, including metal injection, will not operate.

In Figure IX we show a general view of a modified mechanical means for operating the parts of the machine such as shown in Muller Patent 2,184,510, issued July 27, 1954, to the assignee of the present case.

In our die casting mechanism with the electrical control as shown, we employ an hydraulic or oil motor 60 for closing and opening the dies and an air motor 32 for effecting the two-stage molten metal injection, the pressure for the oil being produced by a pump and the air under pressure being supplied from a suitable source, as indicated in the drawings. To this end, we have illustrated in Figures X and XI the detailed construction of one satisfactory valve control means 63a for the oil motor 60, and in Figures XII to XV an air control valve arrangement 84a and associated parts for the motor 32.

Referring to the oil valve 63a, controlled by solenoid 30', and considering Figures X and XI, we have a casing 675, in which is mounted a sliding three-part valve con struction 676, having an extending plunger 677 to `be controlled by solenoid 30.', the plunger also having a further reduced extension 678 around which the coil spring X is positioned between the end shoulder of plunger 677 and the end wall of the casing 675 to return the valve 676 to normal position as shown. As indicated, the spool type sliding valve 676 has three annular chambers 681, 682, and 683.

The piping between the oil pump, the control valve 63a, and the oil motor 60 includes an oil pipe 685 from the pump to the valve 63a, shown on the top of the casing in Figure X. On the bottom of the casing, we have four connections, the pipe 686 leading to the top of the oil motor 68. Each of these pipe connections 686 and 687 has a returning passage 686' and 687 to permit interconnection between the valve 63a and the pump, as will hereinafter appear.

Referring to Figure XI, here the solenoid 30' has been energized and the valve 676 and the plunger`677 has been moved to the right compressing spring X, as shown. In this position the annular passage 682 has now moved to connect the inlet pipe 685 to the pipe 687 so that oil now Hows to the bottom of the motor 60 moving its piston 60a upwardly, as shown in Figures I and Il which operates to close the dies. In this position (Figure XI) the oil from the top of the cylinder 60 will be connected (as also shown in the left hand side of Figure II) to connect the top of the cylinder 60 through pipe 686 valve passage 681 with a passage 686' which forms a return connection to the oil pump.

When in the cycle of operations, the solenoid 30 is deenergized the spring X will return the valve 676 to the left or the position illustrated in Figure X. In this position the oil connection 687 is cut off from the supply 685, but a return therefrom to the pump is established from pipe 687 through valve passage 683 to passage 687. The valve 682 chamber is now connected with the pipe 686 as shown, so that oil passes from inlet pipe 685, valve part 682, pipe 686, to the top of cylinder 60 yand will push the piston 60a downwardly and through the linkages shown and open the dies. (See Figure VI).

Referring to the air valve mechanism, illustrated in Figures XII through XV, it will be seen that the main shaft 83a is illustrated as in Figure I, and the turning of this shaft adjusts the main air valve 84a to the proper v positions as will appear. In one specific embodiment of our invention, this main valve mechanism 84a includes a casing 690, the shaft 83a passing in to the same through a stuing box 691 located on one side as shown. 0n the .other side of the stuffing box, the casing 690 has a special end plate 692, in which aV pluralityof passages y are arranged so that a rotary valve plate mechanism 693, with suitable passages therein, may connect the air inlet and outlet pipes for different connections to eiifect different operations. `Thus, as shown in Figures XII and XIV we have extending from the air supply an inlet pipe 694 into the casing 690, an upwardly extending pipe 695 for connection through the check valve mechanism to the top of the air motor 3.2. Casing 690 also has air exhaust connection 696, and at the lower portion of said casing, a pipe 697 for connection with the bottom of Acylinder 32. Each of these pipes 694 to 697 connect with openings shown on the inner face of the end closure 692, these openings being numbered 694', 695', 696', and 697'.

The movable portion of the valve 84a is illustrated in Figure XV and consists of a rotary plate member 693, having a pair of air passages 701 and 702, each being arc-shaped and terminating in openings 703, 704, 705, and 706 as shown. This plate `693 also has a relief opening 708 to facilitate turning of plate 693. The rod 83a is connected to turn the valve plate 693, and when said valve member 693 is turned in various positions the passages 701 and 702 will connect the various pipes shown in Figure XIV, so that the supply of air under pressure entering through the pipe 694 and opening 694 may be connected through passage 702, openings 704 and 695 hence to pipe 695 to permit air first, through a reduced opening control by a check valve mechanism and later, through a wide open passage to the top of the piston 32a in the motor 32. v

This check valve mechanism 143 (in closed position) is shown in Figure XII whereas in Figure XIII we show the check valve 143 open to permit a full flow of air power to effect the final injection of molten metal into the dies.

One specific embodiment of a check valve'mechanism is here shown, wherein it will be seen that we have a valve -case 710 surrounding and connected with the pipe 695, this casing 710 having the by-pass 142e as shown and a check valve seat 711, both connecting in the casing outlet 712, which is joined to pipe 713, which in turn connects with the upper portion of the air motor 32. The check valve in Fig. XII and Fig. XIII specifically designated as 143 is mounted on a reciprocating shaft 714, which extends to the right, as shown in Figure XII, into an air cylinder portion 71S of the casing 710. A piston 716 is connected to the rod 714 and is adapted to be moved back and forth according to the control of air admitted into cylinder 715, spring 715 operating to close the check valve as indicated. Air inlet pipe 718 is arranged to be controlled by solenoid 61 through a separate air valve control mechanism, similar to the mechanism of Figures X and XI used for the oil motor. It will be seen that in the check valve mechanism indicated generally at 300, spring 715 by its action holds the check valve 143 closed, as shown in Figure XII, whereas when air is admitted into pipe 718, it moves the rod 714 and the piston 716 to the right, as shown in Figure XIII, and removes the check valve 143 from the valve seat 712. This permits a greatly enlarged volume of air from the passage 695 to pass into the pipe 713 and to the top of the air cylinder 32. This forces piston 32a downwardly and to facilitate this action, the other passage 701 of rotary valve 693 is now in the position to exhaust the air below piston 32o by connecting pipe 697 which extends from the bottom of cylinder 32 to casing 690 to an exhaust 696 therefrom.

The operation of member 693 is actuated by shaft 83a and the position of the shaft 83a is controlledby the piston mechanism 332 under the control of solenoid 51, as shown in Figure I. We show in Figure XII one specific embodiment of this construction, where it will be seen that the piston 332 is connected with an upwardly extending rod 720, having a pivotal link connection 721 to oscilv 18 late vthe rod 83a. Thus, when the air controlled by the valve under the control of solenoid 51, as diagrammatically shown in Figure I, is admitted on one side or the other of l,piston 332 it will rotate shaft 03a to one position or the other so as to turn valve member 693 and properly connect the passages 701 and 702, above described, the position for admiting air to the upper side of piston 32a being shown in Figure XII.

When the piston 332 is returned to the botom position of the cylinder 332e, then rod 720 through linlr 721 turns shaft 33a in the opposite direction and rotates valve member 693 clockwise from the position of Figure XV. Then air inlet 694 connects through passage 702 to pipe 697 which pipe connects with the bottom of piston 32a in motor 32 returning the piston upwardly to initial position. Simultaneously the upper portion of cylinder 32 is connected with the exhaust. This is done since the upper part of cylinder 32 is connected by pipe 713, passage 142a, pipe 695 and hence to exhaust 696 since passage 701 now connects pipe 695 with said exhaust 696.

As indicated above, the solenoid 51 illustrated in Figure I for controlling the air valve for cylinder 332 may be of the spool type illustrated for the control of the oil valves in Figures X and XI and further detailed description is deemed unnecessary.

Rsum of crcuits-Fgure VIII From the foregoing electrical circuits, it will be seen that we provide the following main circuits and controls: (l) Power input circut.-Through leads 90, 91 and v92, we supply three phase alternating current, 440 volt current, to the power panel of 'our combination power panel and electrical control mechanism. Y

(2) Transformer and various transformer circuits.- We provide a preliminary transformer 457 for the heat control relay 456 referred to supra and connecting circuits therefor; the main transformer 465 for providing circuits for 220 volt and 110 volt; 24 volt control circuit transformer 482; and the bias circuit transformer 475 all with inter-related circuits, as herein appears.

(3) Machine operating crcuts.-From the foregoing, it will also be seen that we provide a 440 volt circuit for the main machine operating electrical means including the motor for producing oil pressure to operate the die closing mechanism, the coil 30 for operating the electric control kfor die closing, and the coils 51 and 61 for the `two' stage metal injection operating means.

(4) Control crcuits.-We provide several inter-related and interconnected control circuits to properly effect the application of the foregoing machine operating circuits just referred to. These control circuits are supplied with current at 24 volts and primarily are for operating the coils 10', 11 and 12 to, in turn, eifectpan operation of the die closing mechanism and the two stage metal in- .jection referred to. These control circuits are basically controlled by the thyratron tubes 1 and 2, tube 3 being for temporarily resetting bias on tubes 1 and 2 and tube 4 for .effecting opening of the dies and resetting entire bias to initial position. We also provide a control for effecting an operation of the circuit to the oil pressure motor 95' through contacter 442 through push button stage 443. Each of these circuits includes the various relays as hereinbefore set forth, a complete operation Lfollowing this list of circuits. The supply of control Voltage to coil 10 is primarily through relay 402 when the automatic system has been put into operationk by switches 491 and 665 referred to supra and, through the close button manually operated single cycle starting switch 640. For energizing coil 51 (from the power line) .by means of control coil 12, we provide relay 510 con- -nected in the plate circuit of tube 1 for effecting this result, all as hereinafter more fully described. For op erating coil 61 (from the power line) through control coil 11, relay 596 in the plate circuit kof tube 2 produces this action. v

Safety circuits-We provide two solely safety circuits in the switch point 603 of the microswitch, if the latter is not in the correct position, as indicated supra, under the sub-title, Microswitch Must be in Correct Position. We also provide another solely safety 'Circuit in the connection through the switch point 614 of relay 605 to prevent the operation of the metal injection in case the dies are not closed, as described supra, under the subtitle, Circuit to Prevent Relays 11 and 12 from Contacting Until Dies are Closed.

(6) Pilot lamp circuits-From the foregoing description, it is also clear that we provide pilot lamp indicators to advise the operator of the machine the various conditions as referred to in describing said pilot lamps.

Operation-One complete cycle As heretofore indicated, the machine is started by the operator closing the quick return close button 640, in the 24 volt control circuit which is connected to the power inlet and through leads and switches to locking in relay 402, hence, relay 406 and correlated circuits and controls from the relay 430 which is connected with the `24 volt transformer 482 to supply current thereto, through the various circuits, heretofore described and clearly shown in Figure VIII. Closing switch button 640 causes the coil 10 to close the power circuit to the operating coil 30. This action will close the dies of the machine, the action being indicated in Figure I.

More specifically when solenoid 30 is energized as stated, the control valve 63a will be in the'position shown diagrammatically in Figure I with the oil flowing to the bottom of piston 60a as indicated by the arrows. In the actual illustration of a suitable valve 63a as shown in Figures X and XI, the piston valve 676 will be in the position of Figure XI and oil will pass from pump 95 to pipe 685 through valve section 682 to pipe 687 hence to the bottom of piston 60a and move rack 59a upwardly closing die B by the mechanism indicated.

As the dies are closed, the microswitch is operated by a part of the die closing mechanism to thereby throw the microswitch to closed 602 position and effect an energization of relay 605. The machine is held by a mechanical action of a toggle mechanism (disclosed in the Schultz et al. Patent No. 2,173,377, referred to supra). 605 closes switch point 612 .and relay 566 in energized,

Relay opening point 457 'which is in the bias circuit for tube 1,

as described supra. Opening the tube 1 bias permits tube 1 to fire at the end of its time delay through its plate circuit, thereby energizing relay 510, closing switch point 592, as stated supra. This, through the various circuits, above described, energizes relay 12, which in turn supplies power to the solenoid 51 for controlling the main air cylinder 51, valve 84a and permitting a delayed (if desired) injection of metal at reduced pressure to be injected into the die as the tirst part of the two stage metal injection. Specifically, closing of switch point 592 by the discharge of tube 1 connects lead 408 to point 496 of relay 430, point 496 being normally closed, hence to lead 484 of the 24 volt transformer 482 which supplies current back to switch point 592 of relay 510 which in turn connects the current to lead 637, and as clearly shown` in the drawing, to relay 12. The other side of this relay circuit includes leads 636, 635, to point 614 of relay 605 (now closed) through 614, lead 424, 425 to switch 426, lead 485 to transformer 482.

The tiring of tube 1 energizes coil 51 and causes the action illustrated in diagram of Figure II of the drawings, in which the dies, having previously been closed, solenoid air valve 51 permits movement of the piston 332 and the correlated parts, illustrated in the diagram of Figure II, as described supra, thereby turning main air valve `84a to the position shown in Figure II and this permits a slow injection of metal by a slow movement of piston 32a since the air supply thereto passes only through by-pass 142:1

thus moving piston 32a at a relatively low pressure and all air beneath the piston 32a is removed by the adjustment of valve 84a, to the new posiiton shown in Figure II, as described supra. This is an important feature of our invention since we have found that by removing all the air beneath the piston 32a, when the next cycle of operations takes place, it permits a very strong satisfactory injection of main metal into the dies avoiding complicated arrangements heretofore regarded as necessary.

In the specific means shown in Figures XII to XV, it will be seen that when solenoid 61 operates (Figures I and II) it moves the control valve for the supply of air to the bottom of piston 332 which as shown in Figure XII moves piston 332 upwardly so that rod 720 turns shaft 83a by the connection 721. Air inlet pipe 694 and opening 694 is now connected by valve member 693 through passage 702 so that air passes through opening 704 to opening 695', pipe 695 to by-pass 142a, check valve 143 being now closed against its seat 711. Pipe 713 conducts the air under pressure to the top of piston 32a forcing it downwardly. At the same time as shown in Figures XII and XIV, air from beneath piston 32a is exhausted through pipe 697 opening 697 valve passage 701 to openings 705 and 696' to the exhaust 696.

Temporary auxiliary circuit for biasing tubes 2 and 3 It will be noted from the wiring diagram of Figure VIII that we also provide, in addition to the main biasing circuit above described, an auxiliary bias circuit for tubes 2 and 3. To this end it will be noted that we provide a lead 575 from main bias supply lead 565, lead 575 connectcd through normally closed point 576 of relay 510 and lead 590 to the ibas circuit 580, etc., for tube 2. We also provide as described in detail supra, various other auxiliary and temporary bias circuits for tubes 3 and 4. This auxiliary biasing circuit for tubes 2 and 3 is on temporarily simultaneously with the main` bias supply described above.

Firing of tube 2 It will be noted as indicated above, when relay 566 has been energized, the main supply bias at switch points 568 and 569 have also been broken at the same time when the bias supply was broken to tube 1. However, the auxiliary bias supply circuits for tubes 2 and 3 still prevents tubes 2 and 3 from ring.

By the tiring of tube 1, just described, this auxiliary bias for tube 2 is also opened because switch point 576 which is in the bias circuit for tube 2, has now been opened by relay 510. Removing tube 2 bias causes the discharge of its circuit at the end of its time delay and energizes relay 596. Thus, when point 597 is closed, current is supplied from the transformer 482 to relay 11 circuits and switches, since we have provided a lead from the lead 408, numbered 409, to switch point 597 (lead 408 being connccted to transformer 482 as just described), and from switch 597, lead 598 to relay 11. On the other side of relay 11, we have a lead which joins lead 635 described for relay 12. Hence, the connections are established back to the transformer 482, as just described, in connection with tube 1. As will be understood from the foregoing, the energization of relay 11 in turn connects the 440 volt power line to the coil 61 of the air pilot valve 61a (Figure III) turning to the position shown in Figure III, which causes the main injection 0f metal at high pressure into the closed die, since the check valve 143 shown beneath the bypass 142a is also now opened, all as illustrated in Figure III of the drawings.

In Figures XII and XII we show the specific means we have used for opening check valve 143. Here the rod 714 carrying valve 143 is moved by air piston 716 which is moved back and forth at the proper intervals by admitting air under pressure through pipe 718 or 719 to open and close check valve 143 all as appears from .Figures XII and XIII. This air motor is in turn controlled by a solenoid air valve mechanism similar to the one shown for the oil control in Figures X and XI, the 

